Currently, for a greener environment, industry movement is toward using Light Emitting Diodes (LEDs) as a light source to replace the incandescent bulbs, halogen bulbs, and CFLs. LEDs dramatically save on power consumption and electricity bills, and their extended duty life of 50,000 hours is a great improvement over conventional light sources that last perhaps a year or two and burn out. Such LED light fixture implement what is known as an LED light engine. The LED light engine is loosely defined as an integrated assembly made from LED packages (components) or LED arrays, an LED driver, and other optical, thermal, mechanical and electrical components. The LED light engine is intended to connect directly to the branch circuit through a connector compatible with the LED light fixture for which it was designed.
Early LED light fixtures were designed with dedicated LEDs permanently integrated into the fixture. Because the LEDs were dedicated components, it was easier for the designers to control the outflow of the heat generated by early LEDs, to optimize lumens output by the LEDs, and to extend the LED life. Thermal management is important in LED lighting fixtures since it impacts the life and reliability of the LEDs, the efficiency of lumens generated versus energy consumed by the LEDs, and the risk of generating a fire in the fixture.